Blast chiller

Abstract

A chiller having a forced air means and a pressure plenum so as to provide a suitably concentrated and even air flow and distribution through spatial gaps between trays on one or more insertable food racks. The plenum has a high pressure cavity at one end and a low pressure cavity at the opposite end. A motorized fan mounted above the plenum and separated therefrom by a ceiling plate draws chilled air from the low pressure chamber and forces it into the high pressure chamber in front of the plenum. A turning vane directs the air into high pressure chamber and reduces potential turbulence. The walls leading from the high pressure cavity to the plenum are preferably tapered at least in part so as to force air into the plenum in a funnel-like manner, and uniformly through spatial gaps between the trays on the rack or racks. A multi-function controller controls the chilling operation by allowing selection of either a chill time or a target product temperature. An internal probe measures the product temperature and provides sensory information to the multi-function controller.

What is claimed is: 
     
       1. A blast chiller comprising: an insulated housing,   a plenum inside said housing, said plenum comprising a first opening and a second opening,   a high pressure cavity located adjacent to said first opening, said plenum comprising a funnel section connecting said plenum to said high pressure cavity whereby air is compressed from said high pressure cavity into said plenum,   a low pressure cavity located adjacent to said second opening, such that air leaving said plenum is decompressed as it enters said low pressure cavity through said second opening,   a motorized fan positioned in an airpath outside of said plenum and between said high pressure cavity and said low pressure cavity, said motorized fan directed to blow air towards said high pressure cavity and to remove air from said low pressure cavity, and   means for reducing the air temperature within said insulated housing.   
     
     
       2. The blast chiller of claim 1 wherein the funnel section connecting said plenum and said high pressure cavity comprises a pair of tapered walls. 
     
     
       3. The blast chiller of claim 1 wherein said low pressure cavity is box-shaped and has one side connected to said second opening connecting said low pressure cavity to said plenum, said one side being wider and taller than said second opening. 
     
     
       4. The blast chiller of claim 1 wherein said plenum is box-shaped. 
     
     
       5. The blast chiller of claim 1 wherein said plenum conforms closely to the shape of an insertable rack. 
     
     
       6. The blast chiller of claim 1 wherein said means for reducing the air temperature within said insulated housing comprises an evaporator and a condensing unit external to said insulated housing and connected to said evaporator. 
     
     
       7. The blast chiller of claim 1 further comprising a turning vane positioned at the top of said high pressure cavity, said turning vane directly receiving air blown by said fan. 
     
     
       8. The blast chiller of claim 1 further comprising a sensor capable of insertion in a product to be cooled, and means for comparing a measured product temperature with a target product temperature and for terminating a chilling cycle upon said measured product temperature reaching said target product temperature. 
     
     
       9. A blast chiller comprising: an insulated housing,   a plenum inside said housing, said plenum comprising a pair of plenum side walls, a plenum ceiling, a plenum floor, a first opening at a front end of the plenum, and a second opening at a back end of the plenum,   a high pressure chamber located towards the front end of said plenum, said high pressure chamber comprising a pair of high pressure chamber side walls set wider apart than said plenum side walls,   a pair of tapered walls connecting said high pressure chamber side walls to said plenum side walls, such that air forced into said high pressure chamber is compressed into said plenum by said pair of tapered walls,   a low pressure chamber connected by said second opening to the back end of said plenum,   a secondary airpath other than said plenum connecting said high pressure chamber and said low pressure chamber,   a fan disposed outside of said plenum and between said high pressure chamber and said low pressure chamber, such that air is pulled from said low pressure chamber across said secondary airpath and forced into said high pressure chamber, and   a cooling evaporator within said insulated housing.   
     
     
       10. The blast chiller of claim 1 wherein said tapered walls are straight. 
     
     
       11. The blast chiller of claim 10 wherein each of said tapered walls is positioned at an angle of between forty and forty-five degrees with respect to the high pressure chamber side wall to which it is connected. 
     
     
       12. The blast chiller of claim 1 wherein the back end of said plenum is coextensive with said second opening, wherein said low pressure chamber comprises a plurality of sides, with one side connected to said second opening, and wherein the one side of said low pressure chamber is wider and taller than said second opening. 
     
     
       13. The blast chiller of claim 1 wherein said plenum is box-shaped. 
     
     
       14. The blast chiller of claim 1 wherein said plenum conforms closely to the shape of an insertable the rack. 
     
     
       15. The blast chiller of claim 1 further comprising a condensing unit external to said insulated housing and connected to said evaporator. 
     
     
       16. The blast chiller of claim 1 further comprising a turning vane positioned at the top of said high pressure chamber, said turning vane directly receiving air blown by said fan. 
     
     
       17. The blast chiller of claim 1 further comprising a sensor capable of insertion in a product to be cooled, and means for comparing a measured product temperature with a target product temperature. 
     
     
       18. A method of chilling comprising the steps of placing products to be cooled within a plenum, said plenum located within an insulated housing,   forcing air into a high pressure cavity located at one end of said plenum, while simultaneously pulling air out from a low pressure cavity located at an opposite end of said plenum, such that air forced into said high pressure cavity is compressed by a funneling airpath as it moves from said high pressure cavity into said plenum and is decompressed as it exits said plenum and enters said low pressure cavity,   cooling air as it is recirculated from said low pressure cavity to said high pressure cavity, and   suspending said step of cooling upon occurrence of a predetermined condition.   
     
     
       19. The method of claim 18 wherein the step of placing products to be cooled within a plenum comprises the steps of placing said products on trays in a rack and inserting said rack in said plenum. 
     
     
       20. The method of claim 18 further comprising the step of monitoring a temperature of said product to be cooled, wherein said predetermined condition comprises said product reaching a target temperature. 
     
     
       21. The method of claim 18 further comprising the step of measuring a time interval, wherein said predetermined condition comprises said time interval reaching a preset value. 
     
     
       22. A blast chiller comprising an insulated housing,   a rack having a plurality of trays,   a chamber within said insulated housing, said chamber comprising a pair of side panels, a floor and a ceiling plate and conforming closely to the size of said rack, said chamber further comprising a first opening,   a high pressure cavity comprising a second opening, said second opening larger in size than said first opening,   a pair of tapering walls connecting said high pressure cavity and said chamber by connecting said second opening with said first opening, one tapering wall connected to each of said side panels such that air entering said high pressure cavity is compressed into said chamber by said pair of tapering walls,   a low pressure cavity located at another end of said chamber and opposite from said high pressure cavity,   a motorized fan positioned above said ceiling plate and outside of said chamber such that air is removed from said low pressure cavity by said motorized fan and forced across an upper surface of said ceiling plate into said high pressure cavity, and   means for cooling air within said insulated housing.   
     
     
       23. The blast chiller of claim 22 wherein said means for cooling air comprises an evaporator positioned between said chamber and said low pressure cavity, said evaporator connected to a condensing unit. 
     
     
       24. The blast chiller of claim 22 wherein said rack is mobile. 
     
     
       25. The blast chiller of claim 22 further comprising means for sensing a temperature of a product to be cooled, a timer for measuring a chill time, and a controller for suspending a chill operation upon a measured product temperature becoming less than a target product temperature. 
     
     
       26. The blast chiller of claim 25 further comprising a turning vane positioned at the top of said high pressure cavity such that forced air from said motorized fan is directed into said high pressure cavity. 
     
     
       27. A blast chiller comprising: an insulated housing,   a rack comprising a plurality of trays adapted to hold food product, said rack insertable in said insulated housing,   a motorized fan located within said insulated housing, whereby forced air is circulated across said plurality of trays,   means for cooling air within said insulated housing,   a sensor insertable into said food product, said sensor providing a measurement of product temperature,   a controller comprising means for selecting a target product temperature and a preset chill time,   means for comparing said product temperature with said target product temperature,   means for comparing a time of operation of said blast chiller against said preset chill time, and   means for discontinuing operation of said blast chiller upon attainment either of said product temperature with said target product temperature or of said time of operation of said blast chiller with said preset chill time.   
     
     
       28. The blast chiller of claim 27 further comprising a plenum within said insulated housing, said rack insertable within said plenum, wherein said motorized fan is disposed outside of and above said plenum. 
     
     
       29. The blast chiller of claim 27 further comprising means for recording said measurement of product temperature over a time interval. 
     
     
       30. A method of chilling food products comprising the steps of placing food product to be cooled on a plurality of trays,   placing said trays within an insulated chamber,   setting a target product temperature,   selecting a cooling time interval,   cooling air within said insulated chamber,   circulating the cooled air across said trays,   monitoring a length of time of operation of said step of circulating the cooled air across said trays,   monitoring a temperature of said food product, and   suspending at least one of said steps of cooling air within said insulated chamber or circulating the cooled air across said trays when either said food product temperature reaches said target product temperature or said length of time of operation reaches said preset cooling time interval.   
     
     
       31. The method of claim 30 wherein said trays are located on a mobile rack. 
     
     
       32. The method of claim 31 wherein said step of placing food product to be cooled within an insulated chamber comprises the step of placing said mobile rack within a plenum, and wherein said step of circulating the cooled air across said trays comprises the steps of forcing air into a high pressure cavity located at one end of said plenum while simultaneously pulling air out of a low pressure cavity located at an opposite end of said plenum such that air is compressed into said plenum through a funneling airpath and decompressed as it exits said plenum and enters said low pressure cavity.